Even a single flu virus can't sneak by a new nanoparticle sensor developed at the University of Rochester in New York. Researchers at the university's Institute of Optics relied on a highly sensitive laser interferometer to detect individual flu viruses, 5 nanometer gold particles, and 10 nanometer polystyrene particles that were swept past a laser beam in a stream of water. Unlike conventional detection techniques, the laser interferometer sensor does not require that small particles be specially treated or immobilized on a surface for detection. It is also much faster than most other methods, detecting particles at rates of a thousand a second or more. The researchers expect that their detection scheme will lead to effective screening for microbes and biowarfare agents as well as methods for tracking particles inside cells and monitoring water and air contamination.

Narrow Channels Speed Drying, Even When it's Humid Out
J. C. T. Eijkel et al.
Physical Review Letters (forthcoming article, available to journalists on request)

Objects can dry hundreds of times faster than previously thought, even in humid conditions, with the help of thin grooves with sharp edges, according to a new report by researchers from the University of Twente in the Netherlands. They experimented with an array of trapezoid-shaped nanochannels (4 mm long, about 72 nm deep, and between 2 and 30 micrometers wide) etched in glass. The researchers found that the sharp corners of the grooves helped channel water quickly to the edges of the glass, enabling the glass to dry hundreds of times faster than without the sharp-cornered channels. The thinnest channels dried fastest, and relative humidity did not affect the drying rate, up to relative humidity of more than 90%. The results could
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Contact: James Riordon
riordon@aps.org
301-209-3238
American Physical Society
18-Nov-2005